animate a conveyor belt
One technique that might be useful is to turn the motion of a single plank into an NLA strip that repeats in a track.  Then you put that same action into a repeating NLA strip into a track on each other plank, but offset in time, so it follows the same path, but a second or so later than the plank in front of it.



I optimized my workflow by setting up the repeating strip before duplicating the object with Alt-D.  Then all I had to do was grab the strip in the NLA and G X -10